1. Field of the Invention
The present invention relates to extended or further compression of vector quantized encoded and compressed data. More specifically, the present invention relates to further compression by extension of the dimensionality of the vector space by a process of concatenation.
2. Description of the Prior Art
Vector quantization is a known technique or method which has been employed to achieve data compression. Design algorithms have been developed for a variety of vector quantizers and are presented in a scholarly paper entitled "Vector Quantization" by Robert M. Gray in the IEEE Acoustical Speech and Signal Processing (ASSP) Magazine published April 1984 @ pages 4-29 which includes a bibliography of seventy-seven (77) references. It is possible to approach a data compression system problem which involves speech waveforms and image data from the amount of distortion or degradation that will be permitted in the system. Having once decided on the permissible degradation or distortion, the amount of compression or the ratio of data compression may be calculated for the system being designed. Some data compression systems produce more distortion than others and different systems classified as vector quantization encoding systems will produce different amounts of distortion.
Heretofore, vectors representative of a matrix of 2.times.2 pixel blocks of 8-bits have been vector quantized and encoded to provide data compression of up to four to one with very good image quality produced at the decoder. Also, a single vector representative of a matrix of two 2.times.2 pixel blocks of 8-bits each could be vector quantized and encoded to provide the equivalent data compression of up to eight to one with very good image quality produced at the decoder. As will be explained hereinafter, the vector quantization system necessary to achieve this data compression of 8-bit pixels of information into an output of eight encoded bits to achieve an eight to one data compression ratio through the encoder requires an encoder with 2.sup.64 possible inputs with 2.sup.8 outputs. The hardward required to achieve such straight vector quantization is so large and massive so as not to be technically feasible employing the present state of the art technology.
It would be extremely desirable to provide in a single hardware system, a vector quantization and encoding system which would accomplish the aforementioned data compression and would be extremely fast and simple so that it could be packaged into a lightweight system which could be employed for airborne and satellite applications.